One of the strangest Olympics in history will get off to an equally unusual start when the Tokyo 2020 opening ceremony takes place in front of thousands of empty seats on Friday.

Just 1,000 dignitaries will be present at the 68,000-seat Olympic Stadium for the traditional extravaganza, usually a time of celebration for the host nation.

This time around, after a year's pandemic delay, the Japanese public is largely locked out and distrustful of the Games, fearing an influx of infections from the foreign visitors.

The ceremony has been pared back to prevent crowding, with the parade of nations, a centrepiece of the show featuring smiling and waving athletes, dramatically reduced.

Tokyo's Olympic Stadium will be mostly empty for the opening ceremony on Friday
Tokyo's Olympic Stadium will be mostly empty for the opening ceremony on Friday AFP / Behrouz MEHRI

Glimpses of rehearsals witnessed by Tokyo residents suggest a high-tech show including a drone display.

Japan's Emperor Naruhito will be chief among the VIPs, along with a smattering of world leaders and senior figures including US First Lady Jill Biden and French President Emmanuel Macron.

Tokyo 2020 has had a difficult build-up and the opening ceremony is no exception, with a series of sackings of people connected with the show.

The ceremony's director, Kentaro Kobayashi, was fired on the eve of the show over a 1998 comedy sketch referencing the Holocaust.

The opening ceremony is a traditional highlight of the Olympic Games
The opening ceremony is a traditional highlight of the Olympic Games AFP / VANDERLEI ALMEIDA

It came just three days after a composer for the ceremony stepped down following an outcry over past interviews in which he described abusing disabled schoolmates.

The creative director for the opening and closing ceremonies, Hiroshi Sasaki, also resigned in March after suggesting a plus-size female comedian appear as a pig.

The ceremony's focal point is the lighting of the Olympic cauldron, which will conclude a tortuous torch relay that started 16 months ago and has run into several obstacles.

After the flame was lit at a spectator-free ceremony in Olympia, Greece in March last year, the Greek section of the relay was scrapped when a crowd mobbed Hollywood actor Gerard Butler in Sparta.

The flame had barely landed in Japan when the Olympics were postponed and it was put on display around the nation until the relay's restart this March.

However, almost half of the relay legs were taken off public roads or otherwise altered over coronavirus concerns, and fans were kept away when it finally arrived in Tokyo this month.

Virus concerns remain high in Japan, with Tokyo under a state of emergency as the Olympics finally start.

Cases in the capital hit 1,832 on Wednesday -- the highest since January. Experts estimate the number will jump to 2,600 in early August, according to Kyodo news agency.